Albumin catabolic rate and protein-energy depletion.

Severe malnutrition was induced in New Zealand White rabbits by restricting dietary nitrogen and energy to 9.1 and 57.4% of normal intake, respectively. Albumin distribution and metabolism were then determined in these and in control animals. The fractional catabolic rate was reduced by 33.7% in the depleted animals, but there were no changes in the other distribution rate constants. In particular, we were unable to demonstrate a significant change in the relative distribution of albumin between the intravascular and extravascular spaces. In addition, albumin concentration in the depleted group only fell toward the end of the experiment. We conclude that, with acute severe malnutrition, plasma albumin concentration is maintained until late and is therefore not a good nutritional marker. Also, maintenance of intravascular albumin concentration is not at the expense of extravascular albumin.